B4 mileage

[andrewsw]

Well, I geuss I gotta ask over here because no one responded in the general motorcycle mileage thread.

What sort of gas mileage are you guys getting, and with what mods, for your B4?

I get 36-37 mpg (us) with Yosh 4-2-1, K&N filter, no snorkel, 99 main, middle position on the needle, about 3 turns out on the a/f and stock float height. That has me running a touch rich right at 6K, part throttle cruise. but good otherwise, I think.

Is my mileage crap or expected?

A

[PitterB4]

Well, I geuss I gotta ask over here because no one responded in the general motorcycle mileage thread.

What sort of gas mileage are you guys getting, and with what mods, for your B4?

I get 36-37 mpg (us) with Yosh 4-2-1, K&N filter, no snorkel, 99 main, middle position on the needle, about 3 turns out on the a/f and stock float height. That has me running a touch rich right at 6K, part throttle cruise. but good otherwise, I think.

Is my mileage crap or expected?

A

When I had mine set up similarly, I was getting a touch better commuter style riding, 40ish.  I was probably in that range on more spirited rides.  I'm doing better on my nearly-stock zx6r.  I get almost 50 commuting. 

[tomacGTi]

Yep, close to you on setup and last tankup I was at around 40mpgs.

I think even at the trackday the odo said we covered right around 70 miles and I don't think I was below 1/2 tank. I think the culprit may have been a too restrictive fuel filter as I wasn't getting maximum WFO before it felt flat (draining the bowls). That's fixed now.

[andrewsw]

So really, I'm just a little low. I can live with that. I know I'm a touch rich in the mids, which I'll tend to soon. And then I'll have to call it good. My main jet plug chop looks more or less okay. I need to check it again and see how it looks, I could maybe go down to 97.5, but I think that might be too far.

Thanks for the numbers guys.

A

[Vidrazor]

These suckers are real gas-guzzlers. Not sure why. I mean, they're 400cc bikes! You'd think they'd fare better.

[andrewsw]

I know it. I think they're just tuned a little hot from the factory, and not very efficient. Maybe there is something in the way the intake charge mixes so that you don't get a real efficient burn, maybe it's the turbulence from the nakedidity (heh)? who knows. It's frustrating to have to gas up the 400 when the 1200's are getting over 40 mpg.

oh well, I know I have more fun!

[tomacGTi]

Just fueled up and got 38mpgs.

This was with lots of WFO tuning the upper end of my jetting and also to see if the fuel filter I'm using now is flowing more. There was no pussing about on that tank of gas. 87 octane as well.

You have to remember, these bikes have 4 carbs (that are used on larger bikes as well), rev to 14k, have a 11.8-1 compression ratio and generally put out about 50 some odd HP at the crank. It's gotta come from somewhere!

I know riding like a grandpa I can get mid 40's and higher. Also know that even 600 supersports are only known to get in the mid 30's due to their state of tune. I'm just crushed that little under five years ago it would have cost me $5 or so to fill the same bike, now it's about $20.

-Randy

[andrewsw]

I just got about 30 mpg on sunday doing lots of WFO riding. Granted it was pretty windy, and I was running into the wind for most of that... but still. I think I'm low. I don't know, it's all guesswork I suppose until I finally get all the jetting properly sorted.

[VW_NUT]

Hey Randy,

What did you switch to for a fuel filter?

[tomacGTi]

I've got Pingel en route (which I should have done in the first place).

What I did for the meantime was "port" one of those clear glass ones so that there are slots instead of the drilled holes for fluid passage. I used a Dremel basically to connect the holes and turn them into slots as well as reemed out the input and output hole (that sounds horrible) with a drill. I advise doing the reeming before the slotting as there becomes less material for support since the internals are aluminum. I also have a couple of very small neo magnets in there to catch some rust particles that the plastic filter may not catch.

Did not take pics but if you have enough of an imagination, I'm sure you can figure it out.

I'm waiting for the Pingel so I figured I already had this one and it flows much better (via the lung flowbench) versus the VW type 1 style filter and the larger Ford style canister filters I had before. With either of those, on longer WFO applications, you can feel the carbs stutter and starve for fuel. Not so with the sport-tuned model.